The present disclosure relates to a sheet conveying device capable of conveying a sheet member, and an image forming apparatus including the sheet conveying device.
An image forming apparatus such as a multifunctional peripheral has a registration roller for performing a registration operation with respect to a sheet member, and an upstream-side conveying roller disposed upstream of the registration roller. The registration operation performed by the upstream-side conveying roller is an operation of applying a conveying force on a sheet member in a conveying direction in a state where a front end of the sheet member is abutted against a nip portion of the registration roller that is being stopped. When the registration operation is performed, skew of the sheet member that is being conveyed is corrected while the sheet member is flexed just in front of the near side of the registration roller. Then, at a timing when a suitable level of flexure is formed, the registration roller is rotationally driven, and the sheet member is conveyed downstream in the conveying direction. In addition, positioning of an image forming position on the sheet member and a transfer position where an image is to be transferred on the sheet member, becomes possible.
A stepping motor is sometimes used as a drive motor (hereinafter, referred to as registration motor) for driving the registration roller. However, the stepping motor needs to be driven with a sufficiently large torque so as to prevent loss of synchronism even when a large load is applied. Since a large torque needs to be generated, the registration motor has a problem regarding having a large power consumption. Thus, as the registration motor, for example, using a servomotor such as a DC brushless motor is conceivable. A technology of using a DC brushless motor as a drive source of a conveying roller for conveying a sheet from a sheet-feed cassette is known.
When the servomotor is to be used as the registration motor, ordinarily, a detector such as a rotary encoder for detecting a rotating state of the registration roller is disposed, and the registration motor is feedback-controlled based on an output signal of the detector.